Solution to non repetitive request validation in Laravel controller? - php

Question

In my Laravel controllers I am always using the same validation to check if user submitted data is valid/invalid.
public function schedule(Request $request)
{
$request->validate([
'assessment_id' => 'required|integer',
'user_id' => 'required|integer',
'due_date' => 'required|string'
]);
$assessment_id = $request->input('assessment_id');
$user_id = $request->input('user_id');
$due_date = $request->input('due_date');
$staff = auth()->user();
$company = $staff->companies()->first();
$user = $this->staffAssessmentRepository->getUserById($user_id);
$assessment = $this->staffAssessmentRepository->getAssessmentById($assessment_id);
$date = Carbon::parse($due_date);
if(!$user || !$assessment){
return response()->json('Cannot find assessment and/or user!', 404);
}
if(!$company->hasUser($user)){
return response()->json('User does not belong to this company!', 401);
}
if(!$user->hasRole(Role::ROLE_CANDIDATE_NAME)){
return response()->json('User is not a candidate', 401);
}
if($user->hasAssessment($assessment, $company)){
return response()->json('Candidate already has this assessment!', 401);
}
$user_assessment = $this->staffAssessmentRepository->scheduleUserAssessment($user, $company, $assessment, $date, $staff);
if(!$user_assessment){
return response()->json('Failed to create user assessment!', 500);
}
return response()->json($user_assessment, 201);
}
Please look at this specific part from the PHP code above:
if(!$user || !$assessment){
return response()->json('Cannot find assessment and/or user!', 404);
}
if(!$company->hasUser($user)){
return response()->json('User does not belong to this company!', 401);
}
if(!$user->hasRole(Role::ROLE_CANDIDATE_NAME)){
return response()->json('User is not a candidate', 401);
}
if($user->hasAssessment($assessment, $company)){
return response()->json('Candidate already has this assessment!', 401);
}
In my controller methods I am always needing to validate the same user cases, and check if they fail (return response JSON) many times and it's become too repetitive. I'm trying to follow the DRY principle (Don't repeat yourself), and would like your solutions as to how I can prevent repetition in user validation. Solutions can be in PHP/Laravel but I am working in a Laravel project.
EDIT: please not that it isn't the fact that there are many if statements, the issue isn't that. The problem is that the SAME if statements are used amongst multiple different methods in my controllers and I need a architectural decision as to how I can decouple my code so my controllers can inherit the same validation (the if statements).

Answer 1

You should aim to clearly separate the various components of your application, meaning validation should be a single process rather than multiple fragmented processes. Your current approach -- validating some of the input using the Laravel Validator and then manually validating the rest -- is less than ideal.
The ideal approach is to use the Laravel Validator for validating all of the input, including state. There are additional features that can help with this, Form Requests which allow you to implement more advanced validation and re-use validation across multiple controllers, and there's Rule Objects which allow you to implement custom validation logic for attributes.
Your code does the following:
Checks if the User exists
Checks if the Assessment exists
Checks if the User belongs to the Company
Checks if the User is a candidate
Checks if the User already has an assessment
Each of these can be implemented as custom Rules, then you can create a single Form Request which would look something like this:
/**
* Get the validation rules that apply to scheduling an Assessment.
*
* #return array
*/
public function rules(): array
{
return [
'assessment_id' => 'required|exists:assessments',
'user_id' => ['required', 'exists:users', new BelongsToCompany, new IsCandidate],
'due_date' => 'required|date',
];
}
Then for more complex validation (such as validating that the user doesn't already have that assessment which requires 2 input values) you can either have a Rule that you explicitly pass in the additional values or you can use withValidator to extend the validator -- that's covered in the documentation.
Passing in the additional value:
/**
* Get the validation rules that apply to scheduling an Assessment.
*
* #return array
*/
public function rules(): array
{
return [
'assessment_id' => ['required', 'exists:assessments', new AssessmentAvailable(request()->input('user_id'))],
'user_id' => ['required', 'exists:users', new BelongsToCompany, new IsCandidate],
'due_date' => 'required|date',
];
}
Extending the validator:
public function rules(): array
{
// ...
}
/**
* Validates whether or not an assessment is available for the User.
*
* #param \Illuminate\Validation\Validator $validator
*
* #return void
*/
public function withValidator($validator)
{
$validator->after(function ($validator) {
$user = User::findOrFail($this->input('user_id'));
$assessment = Assessment::findOrFail($this->input('assessment_id'));
if ($user->hasAssessment($assessment)) {
$validator->errors()->add('assessment_id', 'The user already has this assessment.');
}
});
}
This approach gives you easy to re-use validation logic and the full power of Laravel's validation system, including input errors for users.